SUmiT Trial Outcomes: Clinical Insights Into Percutaneous Tibial Nerve Stimulation.

HYPOTHESIS / AIMS OF STUDY: Overactive bladder syndrome (OAB) affects the lives of millions of people.  Neuromodulation therapy uses electrical stimulation to target specific nerves in the sacral plexus controlling bladder function.  Urgent^® PC percutaneous tibial nerve stimulation (PTNS) targets the sacral plexus from an accessible, minimally invasive entry point into the nervous system via the posterior tibial nerve.  The objective of this review is to present information about clinical outcomes of PTNS in the 23-center SUmiT Trial for 6 vs. 12 interventions, and for subjects stratified by age.

STUDY DESIGN, MATERIALS AND METHODS: This is an IRB-approved, validated sham-controlled trial evaluating the efficacy of PTNS conducted at 23 U.S. urology and urogynecology centers.  220 subjects (174 females, 46 males) were randomized 1:1 to receive PTNS or validated sham interventions during 30-minute weekly sessions over 12 weeks.  PTNS was percutaneously delivered through a 34-gauge needle electrode inserted near the posterior tibial nerve using the Urgent PC device.  The active surface electrode and 2 sham electrode pads were placed to mimic the sham.  The sham used a Streitberger placebo needle providing the sensation of a needle, but without piercing the skin.  TENS electrode pads placed above and below the small toe provided the sensation of stimulation without tibial nerve activation, and an inactive surface electrode was placed to mimic PTNS.  The audible PTNS device sounds were also reproduced in the sham intervention to diminish auditory variation between groups.  See Figure 1 for illustration of interventions. 

Subjects completed the Global Response Assessment (GRA) and OAB-q questionnaires after 6 and 12 interventions and 3-day voiding diaries after 12 interventions.  Data analysis was stratified for GRA response and OAB-q response after 6 and 12 treatments at the 7 and 13 week follow-up intervals, and the 13 week data was stratified by age.  Sexual function (FSFI and SHIM) was analyzed for men and women at 13 weeks.

Figure 1: (A) PTNS and (B) Sham Treatment Illustrations

RESULTS: In an intent-to-treat analysis at week 13 following 12 treatments, the GRA found 54.5% were responders (moderately or markedly improved) in the PTNS group compared to 20.9% in the sham group (p<0.001).  All PTNS as-followed GRA outcomes were statistically significant at 13 weeks compared to baseline, but outcomes were not significant at 7 weeks (after only 6 PTNS treatments). See Table 1. 

Similarly, OAB-q quality of life questionnaires outcomes were statistically significant for improvement at 13 weeks, but not significant at 7 weeks between treatment groups. Analysis of the 3-day voiding diary parameters show PTNS is statically significant in reducing frequency, nighttime voids, moderate to severe urgency episodes, and urge incontinence episodes after 12 interventions compared to baseline, p<0.0001 for all parameters and time intervals.

The mean age of trial subjects was 62.5 years and 60.2 years, PTNS and sham, respectively.  When GRA and OAB-q results were stratified by age, <65 yrs vs. ≥65 yrs, no significant difference in efficacy was found in either study arm  No significant changes in sexual function indices were reported by either study arm or gender.  No serious treatment related adverse events were reported throughout out the trial.

Table 1: Patient Improvements After 6 and 12 Treatments

Table 2. Comparison of PTNS to Sham Voiding Diary Episodes Per Day at Baseline and 13 Weeks

INTERPRETATION OF RESULTS: Although patients may have improvements after six treatments, twelve 30-minute weekly sessions are needed for subjects to achieve statistically significant, clinically meaningful improvements to their OAB symptoms.  Equivalent results were seen in people <65 yrs, as well as for those ≥65 yrs.

CONCLUDING MESSAGE: Based upon the GRA and OAB-q quality of life response outcomes at 7 and 13 weeks, 12 weekly sessions of PTNS treatments are needed for the treatment to be efficacious for those suffering with OAB syndrome.  PTNS therapy is a safe and efficacious treatment for patients of all ages suffering with OAB syndrome.

Source: Original Presentation